The aim of the present research proposal is to demonstrate and clarify the biochemical regulatory mechanisms controlling terminal differentiation during development of the primary and secondary palate. Preliminary data strongly suggests a role for cyclic nucleotides in this process, thus forming the basis for the studies outlined in this proposal. Demonstration of a regulatory role for cyclic nucleotides in craniofacial development will result in a better understanding of the normal biochemical events involved in palate and lip formation. Knowledge of normal mechanisms regulating these morphogenetic processes will provide a framework for better understanding of etiology of facial clefts at the biochemical level.